Radiation exposure in interventional radiology and other medical imaging modalities has become a serious concern, driven by the growing number of efficacious diagnostic and image-guided minimally invasive procedures and appropriately increasing utilization. This concern has been underlined by a recent FDA initiative to reduce dose in medical imaging. Alleviating this problem is complex because of the many contributing factors, but we believe that one part of the solution is to build X-ray imaging equipment that acquires images at significantly lower dose. In this spirit, we propose in this SBIR Fast-Track application to build a low-dose fluoroscopic system with a large field of view as required for interventional radiology. We expect that the system will reduce entrance X- ray exposure and radiation dose to the patient by a factor of 4 and the occupational dose by at least a factor of 2 at equal image quality as compared to a conventional system. We, Triple Ring Technologies, have developed a scanning-beam digital X-ray (SBDX) system with a small field of view for cardiac interventions, scheduled for release in fall 2010. The system employs a novel imaging geometry with an extended, scanning-beam X-ray source with 9,000 focal spot positions, and a pixelated photon-counting detector. From each focal-spot position, an X-ray beam is cast through an X-ray collimator onto the detector. The final image, composed of up to 9,000 detector images, is reconstructed in real time. The SBDX system has shown a 4-fold dose reduction in adult patients. To achieve the extended FOV, we will use the existing SBDX system and replace the single detector with two laterally spaced detectors. Importantly, this will require a new X-ray collimator and we determined that construction of the new collimator is the highest development risk. We propose to retire this risk in Phase 1 of the SBIR Fast-Track grant. In Phase 2 of the grant, we will build the large FOV system and perform a comparative phantom study of our system against a conventional system to measure entrance exposure, patient and occupational dose savings. Finally, we will perform an observer study in porcine models to validate image quality in comparison to a conventional system. In conclusion, this grant application proposes to reduce the radiation risk in interventional radiology by building and testing a low-dose fluoroscopy system.